CN102549873B - Intelligence expandable type power converter - Google Patents

Abstract

A kind of method and apparatus of intelligent electric power inversion is disclosed herein, can comprise photovoltaic solar cell plate DC power supply the DC inverter sent out be single-phase or three-phase alternating current flow to electrical network.The intelligent single input of multiple different types, dual input, three inputs, four inputs can be connected one, two, three, four and multiple DC power supply easily with multi input power converter, its DC inverter is become alternating current, and is connected together by daisy chain; Its total electricity produced equals the summation of each intelligent expandable type power converter institute energy output.

Description

Smart Scalable Power Inverter

This application claims priority to US Provisional Patent Application Serial No. 61/226,141, filed July 16, 2009, which is hereby incorporated by reference herein.

This patent relates to power inversion from direct current (DC) to alternating current (AC), that is, to invert the direct current of a single or multiple direct current sources into single-phase or three-phase alternating current, where the direct current sources include but are not limited to photovoltaic solar panels, fuel Batteries, accumulators and other DC generating equipment. More specifically, this patent relates to a method and device for intelligently inverting the DC power of a single or multiple DC power sources into single-phase or three-phase AC power and supplying it to the grid with optimal efficiency and system scalability . The intelligent scalable power inverter of the present invention includes an innovative and unique scalable design, so that a DC-to-AC power inverter system can be as small as only an inverter and a DC power supply, or can be Large enough to contain many inverters and multiple DC power supplies. Multiple intelligent single-input, double-input, three-input, four-input and multi-input power inverters can easily connect one, two, three, four and multiple DC power sources to invert DC to AC . The total amount of AC power generated by multiple power inverters connected in a cascade chain is equal to the sum of the AC power generated by each smart scalable power inverter.

In the following description, we will use a photovoltaic (PV) solar power generation system as an example to describe the present invention in detail. Traditionally, in a photovoltaic solar power system, the DC power from each solar panel is combined in a DC junction box. The final DC output of the DC adapter box is connected to a large centralized DC-AC power inverter for power generation. The use of centralized inverters includes the following disadvantages:

1. If the inverter is damaged, the entire solar power generation system will be paralyzed;

2. Centralized power inverters require a large installation space, generate a lot of heat and noise, and are expensive;

3. Because the overall performance of the solar power generation system is constrained by the solar panel with the worst performance in the system, its power production will be affected by the arrangement or performance of the solar panels inconsistently, sunlight changes, or local disturbances caused by clouds, trees, dust on the panels, etc. Negative effects of shadows;

4. Maximum power point tracking (MPPT) can only be applied at the system level instead of each solar panel;

5. It requires a lot of design and installation work to ensure that all solar panels are oriented in the same direction;

6. The DC output of each solar panel needs to be connected to a DC adapter box, resulting in high wiring costs and heavy work;

7. It is necessary to use expensive large-capacity DC cables to connect the DC transfer box and the centralized power inverter to reduce power loss.

The smart scalable power inverter described in this patent can overcome these disadvantages, provide good scalability and flexibility, and make it easy and cost-effective to install a solar power system with optimal power generation efficiency.

In the attached picture:

Figure 1 depicts a block diagram of an intelligent single-input power inverter and optimization system, including a power inverter that converts DC power from a DC power source into single-phase AC power.

Figure 2 describes an intelligent single-input three-phase power inverter and optimization system with a block diagram, including a three-phase power inverter that can invert the DC power of a DC power supply into three-phase AC power.

Figure 3 shows a block diagram of an intelligent single-input power inverter and optimization system, which includes two or more power inverters connected through a cascade chain, where each inverter can connect a DC The direct current of the power supply is converted into single-phase alternating current.

Figure 4 describes an intelligent single-input three-phase power inverter and optimization system with a block diagram, including two or more three-phase power inverters connected through a cascade chain, each of which can convert a The DC power of the DC power supply connected to it is inverted into a three-phase AC power.

Figure 5 describes an intelligent dual-input power inverter and optimization system with a block diagram, including two or more power inverters connected through a cascade chain, where each inverter can connect two The direct current of the direct current power supply is converted into single-phase alternating current.

Figure 6 describes an intelligent multi-input power inverter and optimization system with a block diagram, including two or more power inverters connected through a cascade chain, where each inverter can connect multiple The direct current of the direct current power supply is converted into single-phase alternating current.

Figure 7 describes an intelligent multi-input three-phase power inverter and optimization system with a block diagram, including two or more power inverters connected through a cascade chain, where each inverter can connect multiple The DC power of the connected DC power source is inverted to three-phase AC power.

Figure 8 depicts a block diagram of an intelligent single-input power inverter that inverts DC power from a DC power source into single-phase AC power.

Figure 9 depicts a block diagram of an intelligent dual-input power inverter that inverts DC power from two DC power sources into single-phase AC power.

Figure 10 uses a block diagram to describe an intelligent multi-input power inverter that inverts DC power from multiple DC power sources into single-phase AC power.

Figure 11 uses a block diagram to describe an intelligent single-input three-phase power inverter that inverts the DC power of a DC power supply into three-phase AC power.

Figure 12 uses a block diagram to describe an intelligent multi-input three-phase power inverter that inverts the DC power of multiple DC power sources into three-phase AC power.

Figure 13 uses a block diagram to describe an intelligent power inverter and optimization system capable of generating single-phase AC power, including an intelligent single-input power inverter, an intelligent double-input power inverter, and multiple multi-input power inverters of various types.

Figure 14 uses a block diagram to describe an intelligent power inverter and optimization system that can generate three-phase AC power, including an intelligent double-input power inverter connected through a cascade chain, an intelligent three-input power inverter, and multiple multi-input power inverters of various types.

Figure 15 depicts a flowchart of the main software program running in the MFA microcontroller.

Figure 16 describes the interrupt service routine embedded in the MFA microcontroller with a flowchart, including key components, functions, and steps.

The term "mechanism" is used herein to mean hardware, software, or any combination thereof.

Figure 1 depicts a block diagram of an intelligent single-input power inverter and optimization system, including a power inverter that converts DC power from a DC power source into single-phase AC power. The system includes a power inverter 10, a DC power source (such as a solar panel) 20, an inverter AC output port 12, an inverter DC input port 14, a DC power supply DC connector 16, a DC cables 18 , a single phase AC power line 24 , a switchboard 26 , and grid 28 . This is an example of the simplest DC to AC power inverter and optimization system. It only includes a power inverter connected to a DC power source, which inverts the DC power into a single-phase AC power, and outputs the AC power to the grid 28 through the AC transmission line 24 and the switchboard 26 . If the DC power source is a photovoltaic solar panel, the system can be considered a personal solar power system, which can be installed by competent homeowners with permits.

Figure 2 describes an intelligent single-input three-phase power inverter and optimization system with a block diagram, including a three-phase power inverter that can invert the DC power of a DC power supply into three-phase AC power. The system includes a power inverter 30, a DC power source (such as a solar panel) 40, an inverter AC output port 32, an inverter DC input port 34, a DC power source DC connector 36, a A DC cable 38, a three-phase AC transmission line 44, a three-phase switchboard 46, and a three-phase AC grid 48. The power inverter connected with a DC power source inverts the DC power into three-phase AC power, and outputs the AC power to the grid 48 through the AC transmission line 44 and the switchboard 46 .

Figure 3 shows a block diagram of an intelligent single-input power inverter and optimization system, which includes two or more power inverters connected through a cascade chain, where each inverter can connect a DC The direct current of the power supply is converted into single-phase alternating current. The system includes n intelligent power inverters 50 and the same number of DC power sources 60 . Each intelligent power inverter includes an AC input port 51 , an AC output port 52 , and a DC input port 54 . Each DC power source (such as a solar panel) 60 includes a DC connector 56 and a DC cable 58 that connects to a power inverter. All intelligent power inverters 50 are connected through a cascaded chain; the AC input port 53 of the first power inverter is suspended, and the AC output port 55 of the last power inverter is connected to the switchboard 66 through a single-phase AC transmission line 64 . The alternating current generated by the system is sent to the grid 68 .

In this document, n=1, 2, 3, . . . are integers. Based on the specific design of the smart scalable inverter, the actual number of inverters that can be connected through a cascade chain may be limited to some extent. This is because the total AC current output by the system cannot be greater than the capacity limitations of the branch circuit disconnect switches in the distribution panel. Each switchboard can add multiple branch circuits according to the demand for power generation in actual applications.

Without loss of generality, we take n=16 as an example. This means that 16 smart power inverters can be connected in a cascaded chain. The AC output port of each smart power inverter is connected to the input port of another smart power inverter, and so on. The AC input port of the first power inverter is suspended, and the output port of the last power inverter is connected to an AC distribution panel to transmit the generated AC power to the grid. This method greatly simplifies the wiring work when installing a photovoltaic solar power generation system.

Although we say that the power inverters are connected in a cascade chain, with the output of each power inverter connected to the input of another power inverter, in fact the connection between the inverters is pass-through . That is, the AC power generated from each power inverter is paralleled to the AC transmission line. This way, those defective or low-efficiency inverters will not interfere with other inverters that are generating electricity normally. A defective or inefficient inverter can be automatically shut down by its internal solid-state switching mechanism. Therefore, unless the AC line is damaged, all normal power inverters connected to the AC line will continue to work.

Figure 4 describes an intelligent single-input three-phase power inverter and optimization system with a block diagram, including two or more three-phase power inverters connected through a cascade chain, each of which can convert a The DC power of the DC power supply connected to it is inverted into a three-phase AC power. The system includes n intelligent power inverters 70 and the same number of DC power sources 80 . Each intelligent power inverter includes an AC input port 71 , an AC output port 72 , and a DC input port 74 . Each DC power source (such as a solar panel) 80 includes a DC connector 76 and a DC power cable 78 that connects to a power inverter. All intelligent power inverters 70 are connected through a cascade chain; the AC input port 73 of the first power inverter is suspended, and the AC output port 75 of the last power inverter is connected to the three-phase Switchboard 86. The AC power generated by the system is sent to the grid 88 .

Figure 5 describes an intelligent dual-input power inverter and optimization system with a block diagram, including two or more power inverters connected through a cascade chain, where each inverter can connect two The direct current of the direct current power supply is converted into single-phase alternating current. The system includes n intelligent power inverters 90, and double the number of DC power sources 100, so the total number of DC power sources is 2xn (2 times of n). Each DC power source (such as a solar panel) 100 includes a DC connector 96 . Each intelligent double-input power inverter has two DC input ports 94 and 95 , and are respectively connected to corresponding DC power sources through DC cables 98 and 99 . Each intelligent power inverter includes an AC input port 91 and an AC output port 92 . All intelligent power inverters 90 are connected through a cascade chain; the AC input port 101 of the first power inverter is suspended, and the AC output port 103 of the last power inverter is connected to the switchboard 106 through a single-phase AC transmission line 104 . The AC power generated by the system is sent to the grid 108 .

Figure 6 describes an intelligent multi-input power inverter and optimization system with a block diagram, including two or more power inverters connected through a cascade chain, where each inverter can connect multiple The direct current of the direct current power supply is converted into single-phase alternating current. Without loss of generality, the system includes n smart power inverters 110 , and each smart power inverter includes a plurality of DC input ports 113114 , . . . , 115 . Each DC power supply 120 has a DC connector 116 . For each intelligent multi-input power inverter, m DC power sources 120 are respectively connected to corresponding power inverters through DC cables 117 , 118 . . . , 119 . Each intelligent power inverter includes an AC output port 111 and an AC output port 112 . All intelligent power inverters 110 are connected through a cascaded chain; the AC input port 121 of the first power inverter is suspended, and the AC output port 123 of the last power inverter is connected to the switchboard 126 through a single-phase AC transmission line 124 . The AC power generated by the system is sent to the grid 128 . With this scalable scheme, the system can have nxm (n by m) DC power sources (such as photovoltaic solar panels); where n is the total number of power inverters and m is the DC power connected to each power inverter total number of power supplies.

In this document, m=1, 2, 3, . . . are integers. Smart scalable power inverters can be designed with single input (m=1), dual input (m=2), triple input (m=3), quad input (m=4) and so on. In practical applications, intelligent power inverters can be designed as a variety of products with different numbers of input ports. These products must be practical, meet the capacity constraints of the branch circuit, and be economical for the practical application. Because each intelligent multi-input power inverter can be connected to m DC power sources, it can save a lot of cost compared with a single-input power inverter designed one-to-one. In addition, the AC power interfaces of n intelligent multi-input power inverters can be connected through a cascaded chain, which can significantly reduce the workload of wiring when installing a solar power generation system.

For multiple input power inverters, the actual number of inverters that can be connected in a cascaded chain is limited by the total power generated by all DC sources in that branch circuit subsystem. In the configuration of this example, there are a total of nxm (n times m) DC power supplies. If a branch circuit subsystem can accommodate the power generated by 16 DC sources, we can meet this requirement by connecting 8 dual-input power inverters or 4 quad-input power inverters through a cascade chain. If there are a large number of DC sources in a system, it is usually possible to add more branch circuits at the panel. In this case, the solar power generation system will contain several subsystems, each of which contains nxm DC power sources, n intelligent scalable power inverters and a branch circuit.

Figure 7 describes an intelligent multi-input three-phase power inverter and optimization system with a block diagram, including two or more power inverters connected through a cascade chain, where each inverter can connect multiple The DC power of the connected DC power source is inverted to three-phase AC power. Without loss of generality, the system includes n intelligent multi-input power inverters 130 , and each intelligent power inverter includes m DC input ports 133134 . . . , 135 . Each DC power supply 140 has a DC connector 136 . For each intelligent multi-input power inverter, m DC power sources 140 are respectively connected to corresponding power inverters through DC cables 137 , 138 . . . , 139 . Each intelligent power inverter includes an AC output port 131 and an AC output port 132 . n smart power inverters 130 are connected through a cascaded chain, the AC input port 141 of the first power inverter is suspended, and the AC output port 143 of the last power inverter is connected to the switchboard through a single-phase AC transmission line 144 146. The AC power generated by the system is sent to the grid 148 .

Figure 8 depicts a block diagram of an intelligent single-input power inverter that inverts DC power from a DC power source into single-phase AC power. The smart single input power inverter 150 includes a DC-DC boost converter 154, a DC-AC inverter 156, a load interface circuit 158, a solid-state switching circuit 160, an MFA microcontroller 162, a Line detection circuit 164 , a power line communication interface circuit 166 , a power line communication modem 168 , and a DC power supply 170 .

The MFA microcontroller 162, as well as the MFA microcontrollers shown in FIGS. Combination of central processing unit (CPU) integrated circuits with functions and peripherals such as watchdog, serial and analog input/output channels (I/O), memory modules, pulse width modulation (PWM) generators, and user software programs . A 32-bit high-performance floating-point microcontroller is chosen for this application. MFA microcontrollers perform real-time control and optimization functions for smart and scalable power inverters; among them, the model-free adaptive (MFA) controller is used to control the DC-DC boost converter, and the MFA optimizer provides maximum power point tracking (MPPT) ) enables the power inverter to achieve maximum power output. MFA control and optimization techniques have been described in US Patents 6,055,524, 6,556,980, 6,360,131, 6,684,115, 6,684,112, 7,016,743, 7,142,626, 7,152,052, 7,415,446, as well as related international patents and other pending patents.

In FIG. 8 , power from a DC power source 152 is delivered to a DC-DC boost converter 154 . Example: A standard 24V photovoltaic solar panel can generate up to 8A of DC from a range of 24V to 40V. In order to generate a common 240V AC, the input DC voltage needs to be boosted to at least a usable voltage such as 170VDC. Inductors, capacitors, diodes, switches, controlled PWM (pulse width modulation) signals, etc. can be used to implement a DC boost circuit. The direct current is inverted by the DC-AC inverter 156 into an alternating current with a voltage greater than 240VAC. The generated AC power is combined with the AC power in the internal AC power line 159 through the load interface circuit 158 . The high frequency portion of the alternating current is filtered by the load interface circuit 158 . A solid state switch 160 is controlled by the MFA microcontroller 162 to isolate the internal power line 159 from the external power line 172 when solar is not generating power. In this way, when not generating electricity, the solar power generation unit consumes the least electricity from the grid. The line detection circuit 164 is connected with the AC transmission line 159 and is used for detecting the phase and zero-crossing signal of the AC power from the power grid. The phase and zero-crossing signals are sent to the MFA microcontroller 162 for AC synchronization to ensure high-quality synchronous power delivery to the grid. The power line communication modem 168 is isolated from the power grid through the interface circuit 166, and is used to establish two-way digital communication between the MFA microcontroller 162 and the outside world through the power line. Because the digital signal is already embedded within the AC signal, the system does not require additional digital signal lines. The DC power supply 170 draws power from an external AC power line 172 to provide DC power to the electronic components of the inverter.

The MFA microcontroller 162 is used to perform the following tasks: (i) monitor the DC boost voltage, (ii) control the DC-DC boost converter, (iii) implement maximum power point tracking (MPPT), (iv) implement DC-DC boost converter AC inverter and AC synchronization, (v) measure AC current and voltage and monitor power generation and working status, (vi) implement power line communication, (vii) perform logic control such as AC power line switching and isolation.

Figure 9 depicts a block diagram of an intelligent dual-input power inverter that inverts DC power from two DC power sources into single-phase AC power. The intelligent dual-input power inverter 180 includes two DC-DC boost converters 183, 184, a DC power combiner 185, a DC-AC inverter 186, a load interface circuit 188, and a solid-state switching circuit 190 , an MFA microcontroller 192 , a line detection circuit 194 , a power line communication interface circuit 196 , a power line communication modem 198 , and a DC power supply 200 . Power from DC power sources 181 , 182 is delivered to DC-DC boost converters 183 , 184 respectively; The combined direct currents are converted into alternating currents greater than 240 VAC by the DC-AC inverter 186 . The generated AC power is combined with the AC power in the internal AC power line 189 through the load interface circuit 188 . A solid state switch 190 is controlled by the MFA microcontroller 192 to isolate the internal power line 189 from the external power line 202 when solar is not generating power. The line detection circuit 194 is connected to the AC transmission line 189 and is used for detecting the phase and zero-crossing signal of the AC power from the power grid. The phase and zero-crossing signals are sent to the MFA microcontroller 192 for AC synchronization to ensure high-quality synchronous power delivery to the grid. The power line communication modem 198 is isolated from the power grid through the interface circuit 196, and is used to establish two-way digital communication between the MFA microcontroller 192 and the outside world through the power line. The DC power supply 200 extracts power from the external AC power line 202 to provide DC power for the electronic components of the inverter. The MFA microcontroller 192 is used to perform the following tasks: (i) monitor the DC boost voltage of each DC-DC boost converter, (ii) control the DC-DC boost converter, (iii) implement maximum power point tracking (MPPT), (iv) implement DC-AC inverter and AC synchronization, (v) measure AC current and voltage and monitor power generation and status, (vi) implement power line communication, (vii) perform AC power line switching and isolation And so on logic control.

Figure 10 uses a block diagram to describe an intelligent multi-input power inverter that inverts DC power from multiple DC power sources into single-phase AC power. The intelligent multi-input power inverter 206 includes m DC-DC step-up converters 212, 213, . . . , 214, a DC power combiner 215, a DC-AC inverter 216, and a load interface circuit 218 , a solid state switching circuit 220 , an MFA microcontroller 222 , a line detection circuit 224 , a power line communication interface circuit 226 , a power line communication modem 228 , and a DC power supply 230 . Power from DC power sources 208 , 209 , . . . , 210 are delivered to DC-DC boost converters 212 , 213 , . The merged direct currents are converted into alternating currents greater than 240 VAC through the DC-AC inverter 216 . The generated AC power is combined with the AC power in the internal AC power line 219 through the load interface circuit 218 . A solid state switch 220 is controlled by the MFA microcontroller 222 to isolate the internal power line 219 from the external power line 232 when solar is not generating power. The line detection circuit 224 is connected to the AC transmission line 219 and is used for detecting the phase and zero-crossing signal of the AC power from the power grid. The phase and zero-crossing signals are sent to the MFA microcontroller 222 for AC synchronization to ensure high-quality synchronous power delivery to the grid. The power line communication modem 228 is isolated from the power grid through the interface circuit 226, and is used to establish two-way digital communication between the MFA microcontroller 222 and the outside world through the power line. The DC power supply 230 extracts power from the external AC power line 232 to provide DC power for the electronic components of the inverter. The MFA microcontroller 222 is used to perform the following tasks: (i) monitor the DC boost voltage of each DC-DC boost converter, (ii) control the DC-DC boost converter, (iii) implement maximum power point tracking (MPPT), (iv) implement DC-AC inverter and AC power synchronization, (v) measure AC current and voltage and monitor power generation and working status, (vi) implement power line communication, (vii) perform AC power line switching and Logic control such as isolation.

Figure 11 uses a block diagram to describe an intelligent single-input three-phase power inverter that inverts the DC power of a DC power supply into three-phase AC power. The intelligent three-phase single input power inverter 236 includes a DC-DC boost converter 242, a DC-AC inverter 246, a load interface circuit 248, a solid-state switching circuit 250, an MFA microcontroller 252, A line detection circuit 254 , a power line communication interface circuit 256 , a power line communication modem 258 , and a DC power supply 260 . The power from the DC power source 238 is delivered to the DC-DC boost converter 242 to boost the voltage to a certain value. The direct current is converted into a three-phase alternating current greater than 208 VAC through the DC-AC inverter 246 . The generated AC power is combined with the AC power in the internal AC power line 249 through the load interface circuit 248 . A solid state switch 250 is controlled by the MFA microcontroller 252 to isolate the internal three-phase power line 249 from the external three-phase power line 262 when solar is not generating power. The line detection circuit 254 is connected to the AC transmission line 249 and is used for detecting the phase and zero-crossing signal of the three-phase AC power from the power grid. The phase and zero-crossing signals are sent to the MFA microcontroller 252 for AC synchronization to ensure high-quality synchronous three-phase AC transmission to the grid. The power line communication modem 258 is isolated from the power grid through the interface circuit 256, and is used to establish two-way digital communication between the MFA microcontroller 252 and the outside world through the power line. The DC power supply 260 extracts power from the external three-phase AC transmission line 262 to provide DC power for the electronic components of the inverter. The MFA microcontroller 252 is used to perform the following tasks: (i) monitor the DC boost voltage, (ii) control the DC-DC boost converter, (iii) implement maximum power point tracking (MPPT), (iv) implement DC-DC boost converter AC inverter and AC synchronization, (v) measure AC current and voltage and monitor power generation and working status, (vi) implement power line communication, (vii) perform logic control such as AC power line switching and isolation.

Figure 12 uses a block diagram to describe an intelligent multi-input three-phase power inverter that inverts the DC power of multiple DC power sources into three-phase AC power. The intelligent multi-input three-phase power inverter 266 includes m DC-DC step-up converters 272, 273, ..., 274, a DC power combiner 275, a DC-AC inverter 276, A load interface circuit 278 , a solid state switching circuit 280 , an MFA microcontroller 282 , a line detection circuit 284 , a power line communication interface circuit 286 , a power line communication modem 288 , and a DC power supply 290 . Power from DC power sources 268 , 269 , . . . , 270 is delivered to DC-DC boost converters 272 , 273 , . The merged direct current is converted into a three-phase alternating current greater than 208 VAC through the DC-AC inverter 276 . The generated AC power is combined with the AC power in the internal AC power line 279 through the load interface circuit 278 . A solid state switch 280 is controlled by the MFA microcontroller 282 to isolate the internal three-phase power line 279 from the external three-phase power line 292 when solar is not generating power. The line detection circuit 284 is connected to the AC transmission line 279 and is used for detecting the phase and zero-crossing signal of the three-phase AC power from the power grid. The phase and zero-crossing signals are sent to the MFA microcontroller 282 for synchronization of the AC power to ensure high-quality synchronous power delivery to the grid. The power line communication modem 288 is isolated from the power grid through the interface circuit 286, and is used to establish two-way digital communication between the MFA microcontroller 282 and the outside world through the power line. The DC power supply 290 extracts power from an external three-phase AC transmission line 292 to provide DC power for the electronic components of the inverter. The MFA microcontroller 282 is used to perform the following tasks: (i) monitor the DC boost voltage of each DC-DC boost converter, (ii) control the DC-DC boost converter, (iii) implement maximum power point tracking (MPPT), (iv) implement DC-AC inverter and AC power synchronization, (v) measure AC current and voltage and monitor power generation and working status, (vi) implement power line communication, (vii) perform AC power line switching and Logic control such as isolation.

The DC-DC boost converter used in this patented embodiment may be described in the book "Power Electronics Handbook" (Power Electronics Handbook) edited by MuhammadH.Rashid and published by Academic Press (Academic Press) in 2007 Any of the well-known converters, including Buck converter, boost converter, Buck boost converter, super boost-Roche converter, and cascode boost converter. The DC-AC inverter used in this patented embodiment can be any of the well-known DC-AC inverters described in the same book, including half-bridge inverters, full-bridge inverters, two stage PWM inverters, unipolar PWM inverters and sine wave PWM inverters. The DC power combiner used in this patent implementation can be designed as a circuit capable of connecting the outputs of each DC-DC boost converter in parallel, so that the DC output currents of each channel can be superimposed. The power modem used in this patented embodiment can be any integrated circuit on the market that can provide two-way digital communication over power lines. Other modules involved in this patent implementation include load interface, solid-state switch, line measurement circuit, power line interface circuit, and DC power supply, etc., which can be realized by one or more known electronic components, including resistors, capacitors, inductors, solid-state Switches, transformers, diodes, transistors, operational amplifiers and ceramic filters, etc.

Figure 13 uses a block diagram to describe an intelligent power inverter and optimization system capable of generating single-phase AC power, including an intelligent single-input power inverter, an intelligent double-input power inverter, and multiple multi-input power inverters of various types. The system includes an intelligent single-input power inverter 300 , an intelligent double-input power inverter 302 , and n−2 (n minus 2) intelligent multi-input power inverters 304 . The intelligent single-input power inverter 300 inverts the DC power from the DC power source 330 into AC power, the smart dual-input power inverter 302 inverts the DC power from the DC power sources 332 and 334 into AC power, and the multi-input power inverter 304 inverts DC power from DC power sources 336, 338 and 340 to AC power. The single input power inverter 300 is connected to a DC power source 330 through a DC input port 318 , a DC connector 342 of the DC power source, and a DC cable 348 . Dual input power inverter 302 is connected to DC power sources 332 and 334 through DC input ports 320 and 322 , DC power source DC connector 344 and DC cables 350 and 352 , respectively. Multi-input power inverter 304 is connected to DC power sources 336, 338, and 340 through DC input ports 324, 326, and 328, DC power source DC connector 346, and DC cables 354, 356, and 358, respectively.

The intelligent single-input power inverter includes an AC input port 314 and an AC output port 316; the intelligent dual-input power inverter includes an AC input port 310 and an AC output port 312; the intelligent multi-input power inverter It includes an AC input port 306 and an AC output port 308 . Without loss of generality, usually a system can contain multiple smart power inverters with mixed input types. All intelligent scalable power inverters are connected through a cascaded chain, the AC input port 306 of the first power inverter is suspended, and the AC output port 316 of the last power inverter is connected to the switchboard 366 through the AC power line 364 . The electricity generated by the system is sent to the grid 368 .

Figure 14 uses a block diagram to describe an intelligent power inverter and optimization system that can generate three-phase AC power, including an intelligent double-input power inverter connected through a cascade chain, an intelligent three-input power inverter, and multiple multi-input power inverters of various types. The system includes an intelligent dual-input power inverter 370 , an intelligent three-input power inverter 372 , and n−2 (n minus 2) multi-input power inverters 374 . A dual input power inverter 370 converts DC power from two DC power sources 376 to AC power, a triple input power inverter 372 converts DC power from three DC power sources 378 to AC power, and a multi-input power inverter 374 converts The DC power from the plurality of DC power sources 380 is inverted to AC power. Without loss of generality, usually a system can contain multiple smart power inverters with mixed input types. All intelligent scalable power inverters are connected through a cascaded chain, the AC input port of the first power inverter is suspended, and the AC output port of the last power inverter is connected to the switchboard 386 through the AC power line 384 . The electricity generated by the system is sent to the grid 388 .

Figure 15 depicts a flowchart of the main software program running in the MFA microcontroller. In program block 390, the device layer, peripheral layer, system layer, interrupt service routine, and analog and digital control programs of the microcontroller are initialized first. More specifically, initialization will include, but is not limited to, setting up registers, I/O interfaces, timers, and activating internal interrupts in the interrupt service routine. Finally set 'task=1'.

In the main program, there are two main tasks. Task 1 concerns the control and management of an intelligent scalable power inverter. Task 2 involves the power inverter communicating with the outside world via the power line communication modem. After the initialization is completed, the main program enters the main loop entry 392 and executes the program block 394 .

At block 394, the program checks to see if Task 1 is scheduled to run. If the answer is Yes (yes), the function of executing program block 396 includes: (i) opening or closing the relevant generating circuit according to the conditions of the DC input power supply, the power inverter, and the AC transmission line; (ii) calculating Statistical values of electric power such as total power generation in a period of time; (iii) Execute system diagnostic procedures. The program then sets 'task=2' and returns to main loop entry 392. The main program continues to run, and will arrive at program piece 398 through program piece 394. At block 398, the program checks to see if Task 2 is scheduled to run, and if the answer is Yes, the functions of block 400 are performed, which include: (i) setting the unit address for the power inverter, (ii) responding from the data acquisition device request to report the status of power generation. The program then sets 'task=1' and returns to the main loop entry 392. The main program executes the scheduled tasks continuously according to the preset cycle period. When an interrupt occurs, the microcontroller will immediately execute the pending interrupt service routine.

Figure 16 describes the interrupt service routine embedded in the MFA microcontroller with a flowchart, including key components, functions, and steps. Block 402 is the entry point for an Interrupt Service Routine (ISR). An interrupt service routine is a software routine called by the microcontroller in response to an interrupt. All functions that need to be executed according to timing in the microcontroller are implemented in the ISR to ensure its real-time performance. At block 404, the ISR saves the current state of the main program. At block 406, the ISR reads analog and digital inputs including, but not limited to, DC power supplies, DC-DC boost converters, voltage and current signals in DC-AC inverter circuits, and AC phase and zero-crossing signals. At block 408, the ISR executes the MFA optimizer to make each DC power supply circuit reach the maximum power tracking point. At block 410, the ISR performs DC-AC inversion and AC synchronization. At block 412, the PWM control signal is provided to the DC-DC boost converter and DC-AC inverter circuit through the digital output port. At block 414, the ISR restores the state of the main routine prior to entering the interrupt routine. After the interrupt service routine (ISR) exits, the main program will continue to execute the tasks performed before entering the interrupt routine.

This patent demonstrates the scalable nature of this invention by means of illustrations, particularly by the system described in FIGS. 1 , 2 , 13 and 14 . People can use different numbers and sizes of intelligent scalable power inverters to build a small or very large-scale photovoltaic solar power generation system. Regardless of the number and type of DC power sources connected to each power inverter, the same series of intelligent power inverters can be connected and generate electricity through a cascaded chain. This "anythinggoes" design significantly improves the scalability, flexibility, user-friendliness, and return on investment of renewable energy generation systems, including photovoltaic solar power generation systems. Additionally, existing systems can easily be expanded by installing more solar panels and smart power inverters. The ability to scale sustainably with only additional investment makes solar power systems attractive to families and businesses on a budget. This invention will be of strategic importance to the renewable energy industry and society.

Claims (10)

1. A system for delivering alternating current to a grid, the system deriving power from a plurality of single direct current sources having direct current output ports, said system comprising: A plurality of power inverters, each of which has m DC input ports, AC input ports, and AC output ports, each of the DC input ports is connected to a DC power supply, and m is greater than or equal to 2 an integer of Among the multiple power inverters, the AC output port of each power inverter is connected to the AC input port of the next power inverter through a cascaded chain, and only the AC output port of the first power inverter The input port is suspended, and the AC output port of the last power inverter is connected to the grid switchboard; each of said power inverters contains: m DC-DC boost converters, each of which is connected to one of said DC power sources and configured to convert the power supply voltage to a higher DC voltage suitable for inversion; a DC power combiner connected to the m DC-DC boost converters, the DC power combiner is used to combine the DC outputs of all DC-DC boost converters and enable the DC-DC boost converters A parallel connection adds all the DC currents together; a DC-AC inverter connected to the DC power combiner, the DC-AC inverter configured to invert direct current into alternating current, the voltage of the DC-AC inverter being higher than the input AC voltage ; Internal transmission lines for combining the generated alternating current and the external alternating current from the grid; a load interface circuit connecting the DC-AC inverter to an internal AC power line, the load interface circuit being configured to filter high-frequency components of the AC output of the DC-AC inverter; a model-free adaptive microcontroller coupled to the DC-DC boost converter, DC-AC inverter, and interface load circuit, the model-free adaptive microcontroller configured to monitor the DC boost voltage, control DC-DC boost converter, realize maximum power point tracking, realize DC-AC inverter and AC power synchronization, detect AC current and voltage and calculate power generation and status, realize power line communication, and perform logic control of AC power line switching and isolated logic control; a power line modem connected to the model free adaptive microcontroller and connected to an internal power line through an interface circuit, the power line modem transmitting and receiving between the model free adaptive microcontroller and the grid performance data; a line detection circuit connected to the internal power line and the model-free adaptive microcontroller, the line detection circuit for detecting the phase and zero-crossing signal of the input alternating current from the grid; and A solid state switch connected to the internal AC power line and the external AC power line, the solid state switch configured to disconnect the internal power line from the AC grid when not generating power. 2. The system of claim 1, wherein the output of each of the power inverters is single-phase alternating current or three-phase alternating current. 3. A DC-AC power inverter comprising: at least two direct current input ports, each of which is connected to a direct current power source; an AC output port configured to deliver AC power to the grid, wherein, corresponding to each DC power supply, the inverter includes a DC-DC boost converter connected to the DC power supply, the DC ‐DC boost converter configured to convert the mains voltage to a higher DC voltage suitable for inversion; a DC power combiner connected to a plurality of DC-DC boost converters for combining the DC outputs of all DC-DC boost converters and enabling the DC-DC boost converters to be connected in parallel Add all DC currents together; a DC-AC inverter connected to the DC-DC boost converter, the DC-AC inverter is configured to invert direct current into alternating current, the voltage of the DC-AC inverter is higher than the input alternating current higher voltage; Internal transmission lines for combining the generated alternating current and the external alternating current from the grid; a load interface circuit connecting the DC-AC inverter to an internal AC power line, the load interface circuit being configured to filter high-frequency components of the AC output of the DC-AC inverter; a model-free adaptive microcontroller coupled to the DC-DC boost converter, DC-AC inverter, and interface load circuit, the model-free adaptive microcontroller configured to monitor the DC boost voltage, control DC-DC boost converter, realize maximum power point tracking, realize DC-AC inverter and AC power synchronization, detect AC current and voltage and calculate power generation and status, realize power line communication, and perform logic control of AC power line switching and isolated logic control; a power line modem connected to the model free adaptive microcontroller and connected to an internal power line through an interface circuit, the power line modem transmitting and receiving between the model free adaptive microcontroller and the grid performance data; a line detection circuit connected to the internal power line and the model-free adaptive microcontroller, the line detection circuit for detecting the phase and zero-crossing signal of the input alternating current from the grid; and A solid state switch connected to the internal AC power line and the external AC power line, the solid state switch configured to disconnect the internal power line from the AC grid when not generating power. 4. The DC-AC power inverter according to claim 3, wherein the output of each said power inverter is a single-phase alternating current or a three-phase alternating current. 5. A scalable DC-AC power inverter system, the scalable DC-AC power inverter system obtains electrical energy from a plurality of single DC power sources with DC output ports and delivers AC power to the grid, the scalable Type DC-AC power inverter system includes: a plurality of power inverters, each having at least two DC input ports, an AC input port, and an AC output port, each of the DC input ports being connected to a DC power source; Among the multiple power inverters, the AC output port of each power inverter is connected to the AC input port of the next power inverter through a cascaded chain, and only the AC output port of the first power inverter The input port is floating, the AC output port of the last power inverter is connected to the grid switchboard; and Wherein, the scalable DC-AC power inverter system can be gradually expanded by increasing or decreasing the number of DC power sources and inverters connected by cascaded chains. 6. The scalable DC-AC power inverter system according to claim 5, wherein the output of each of the power inverters is single-phase alternating current or three-phase alternating current. 7. The scalable DC-AC power inverter system according to claim 5 or claim 6, wherein each of the scalable DC-AC power inverters comprises: an AC output port configured to deliver AC power to the grid, wherein, corresponding to each DC power source, the power inverter includes a DC-DC boost converter connected to the DC power source, and the DC-DC boost converter a converter configured to convert the mains voltage to a higher DC voltage suitable for inversion; a DC power combiner connected to said plurality of DC-DC boost converters for combining the DC outputs of all DC-DC boost converters and enabling said DC-DC boost converters to be connected in parallel to combine all DC The currents are superimposed together; a DC-AC inverter connected to the DC-DC boost converter, the DC-AC inverter is configured to invert direct current into alternating current, the voltage of the DC-AC inverter is higher than the input alternating current higher voltage; Internal transmission lines for combining the generated alternating current and the external alternating current from the grid; a load interface circuit connecting the DC-AC inverter to an internal AC power line, the load interface circuit being configured to filter high-frequency components of the AC output of the DC-AC inverter; a model-free adaptive microcontroller coupled to the DC-DC boost converter, DC-AC inverter, and interface load circuit, the model-free adaptive microcontroller configured to monitor the DC boost voltage, control DC-DC boost converter, realize maximum power point tracking, realize DC-AC inverter and AC power synchronization, detect AC current and voltage and calculate power generation and status, realize power line communication, and perform logic control of AC power line switching and isolated logic control; a power line modem connected to the model free adaptive microcontroller and connected to an internal power line through an interface circuit, the power line modem transmitting and receiving between the model free adaptive microcontroller and the grid performance data; a line detection circuit connected to the internal power line and the model-free adaptive microcontroller, the line detection circuit for detecting the phase and zero-crossing signal of the input alternating current from the grid; and A solid state switch connected to the internal AC power line and the external AC power line, the solid state switch configured to disconnect the internal power line from the AC grid when not generating power. 8. A method for gradually expanding a DC-AC power inverter system, the method comprising: providing a plurality of DC power sources and a plurality of DC-AC power inverters, each of said DC-AC power inverters having an AC input port, an AC output port, and at least two DC input ports; connecting a DC power source of the plurality of DC power sources to each of the DC input ports; and Connecting at least two of the DC-AC power inverters through a cascade chain, wherein the AC output port of each DC-AC power inverter is connected to the AC output port of the next DC-AC power inverter through the cascade chain For the input port, only the AC input port of the first DC-AC power inverter is suspended, and the AC output port of the last DC-AC power inverter is connected to the grid switchboard; Wherein, the total AC power generated is the sum of the AC power provided by each of the DC-AC power inverters. 9. The method of claim 8, wherein the output of each of said DC-AC power inverters is single-phase alternating current or three-phase alternating current. 10. A method as claimed in claim 8 or claim 9, wherein each said DC-AC power inverter comprises: An AC output port is configured to deliver AC power to the grid, wherein, for each DC power source, the DC-AC power inverter includes a DC-DC boost converter connected to the DC power source, the DC-DC A boost converter is configured to convert the mains voltage to a higher DC voltage suitable for inversion; a DC power combiner connected to the plurality of DC-DC boost converters for combining the DC outputs of all DC-DC boost converters and enabling the DC-DC boost converters A parallel connection adds all the DC currents together; a DC-AC inverter connected to the DC-DC boost converter, the DC-AC inverter is configured to invert direct current into alternating current, the voltage of the DC-AC inverter is higher than the input alternating current higher voltage; Internal transmission lines for combining the generated alternating current and the external alternating current from the grid; a load interface circuit connecting the DC-AC inverter to an internal AC power line, the load interface circuit being configured to filter high-frequency components of the AC output of the DC-AC inverter; a model-free adaptive microcontroller coupled to the DC-DC boost converter, DC-AC inverter, and interface load circuit, the model-free adaptive microcontroller configured to monitor the DC boost voltage, control DC-DC boost converter, realize maximum power point tracking, realize DC-AC inverter and AC power synchronization, detect AC current and voltage and calculate power generation and status, realize power line communication, and perform logic control of AC power line switching and isolated logic control; a power line modem connected to the model free adaptive microcontroller and connected to an internal power line through an interface circuit, the power line modem transmitting and receiving between the model free adaptive microcontroller and the grid performance data; a line detection circuit connected to the internal power line and the model-free adaptive microcontroller, the line detection circuit for detecting the phase and zero-crossing signal of the input alternating current from the grid; and A solid state switch connected to the internal AC power line and the external AC power line, the solid state switch configured to disconnect the internal power line from the AC grid when not generating power.